Hypoxanthine phosphoribosyltransferase activity in tissues and hypoxanthine concentrations in plasma and CSF of the horse in comparison with other species.
1. Plasma hypoxanthine and xanthine concentrations are very low in the horse and low in rat, mouse and greyhound compared to concentrations in beagles, man, sheep and rabbit. 2. Activities in erythrocytes of the main enzyme metabolizing hypoxanthine, hypoxanthine phosphori-bosyltransferase, show a similar pattern (Tax et al., 1976, Comp. Biochem. Physiol. 54B, 209-212); thus low activities have been found where plasma concentrations were low. 3. Hypoxanthine phosphoribosyltransferase activities in horse tissue other than erythrocytes are similar to those in man and rabbit with high activities in brain; this enzyme may therefore be functionally important in equine brain.
Harkness
R A
RA
Division of Inherited Metabolic Diseases, MRC Clinical Research Centre, Harrow, Middlesex, UK.
McCreanor
G M
GM
Allsop
J
J
Snow
D H
DH
Harris
R C
RC
Rossdale
P O
PO
Ousey
J C
JC
D000255:Adenosine Triphosphate / Q000378:metabolism; D000818:Animals; D004285:Dogs; D006736:Horses / Q000378:metabolism*; D006801:Humans; D019271:Hypoxanthine; D007041:Hypoxanthine Phosphoribosyltransferase / Q000378:metabolism*; D007042:Hypoxanthines / Q000097:blood* / Q000134:cerebrospinal fluid; D051379:Mice; D005082:Physical Exertion / Q000502:physiology; D011817:Rabbits; D051381:Rats; D013045:Species Specificity; D014018:Tissue Distribution
D007042:Hypoxanthines; D019271:Hypoxanthine; D000255:Adenosine Triphosphate; D007041:Hypoxanthine Phosphoribosyltransferase